BUG: Insert then delete column into MultiIndex with timestamps leads to RecursionError #56853
Description
Pandas version checks
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I have confirmed this bug exists on the latest version of pandas.
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I have confirmed this bug exists on the main branch of pandas.
Reproducible Example
import pandas as pd
# multiindex with the second level being a Timestamp
df = pd.DataFrame({('A', pd.Timestamp('2024-01-01')): [0]})
# insert using only the top level
df.insert(1, 'B', [1])
print(df.to_string())
# A B
# 2023-01-01 NaT
# 0 0 1
# raises RecursionError
del df['B']Issue Description
Creating and deleting a column is leading to an unexpected error.
This is a contrived example, but was observed in wild when joining two dataframes which had MultiIndex columns with str and timestamp levels with a named index, say 'Index'. The join ends up adding a column ('Index', pd.NaT) then deleting it to set it as the index.
Expected Behavior
It should just delete the column.
del df['B']
print(df.to_string())
# A
# 2023-01-01
# 0 0 Installed Versions
INSTALLED VERSIONS
commit : a671b5a
python : 3.11.7.final.0
python-bits : 64
OS : Darwin
OS-release : 22.5.0
Version : Darwin Kernel Version 22.5.0: Mon Apr 24 20:51:50 PDT 2023; root:xnu-8796.121.2~5/RELEASE_X86_64
machine : x86_64
processor : i386
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8
pandas : 2.1.4
numpy : 1.26.3
pytz : 2023.3.post1
dateutil : 2.8.2
setuptools : 68.2.2
pip : 23.3.1
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : None
IPython : 8.20.0
pandas_datareader : None
bs4 : None
bottleneck : 1.3.5
dataframe-api-compat: None
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : None
numba : None
numexpr : 2.8.7
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None